Capacity Bounds and User Identification Costs in Rayleigh-Fading Many-Access Channel

05/12/2021
by   Jyotish Robin, et al.
0

Many-access channel (MnAC) model allows the number of users in the system and the number of active users to scale as a function of the blocklength and as such is suited for dynamic communication systems with massive number of users such as the Internet of Things. Existing MnAC models assume a priori knowledge of channel gains which is impractical since acquiring Channel State Information (CSI) for massive number of users can overwhelm the available radio resources. This paper incorporates Rayleigh fading effects to the MnAC model and derives an upper bound on the symmetric message-length capacity of the Rayleigh-fading Gaussian MnAC. Furthermore, a lower bound on the minimum number of channel uses for discovering the active users is established. In addition, the performance of Noisy Combinatorial Orthogonal Matching Pursuit (N-COMP) based group testing (GT) is studied as a practical strategy for active device discovery. Simulations show that, for a given SNR, as the number of users increase, the required number of channel uses for N-COMP GT scales approximately the same way as the lower bound on minimum user identification cost. Moreover, in the low SNR regime, for sufficiently large population sizes, the number of channel uses required by N-COMP GT was observed to be within a factor of two of the lower bound when the expected number of active users scales sub-linearly with the total population size.

READ FULL TEXT
research
03/30/2023

Active User Identification in Fast Fading Massive Random Access Channels

Reliable and prompt identification of active users is critical for enabl...
research
09/04/2021

Low SNR Capacity of Keyhole MIMO Channel in Nakagami-m Fading With Full CSI

In this paper, we derive asymptotic expressions for the ergodic capacity...
research
10/21/2022

Message Transmission and Common Randomness Generation over MIMO Slow Fading Channels with Arbitrary Channel State Distribution

We investigate the problem of message transmission and the problem of co...
research
10/18/2020

Deterministic Identification Over Fading Channels

Deterministic identification (DI) is addressed for Gaussian channels wit...
research
12/06/2022

Deterministic K-identification For Slow Fading Channel

Deterministic K-identification (DKI) is addressed for Gaussian channels ...
research
04/19/2018

A Simple Capacity Lower Bound for Communication with Superimposed Pilots

We present a novel closed-form lower bound on the Gaussian-input mutual ...
research
03/11/2023

Non-Coherent Active Device Identification for Massive Random Access

Massive Machine-Type Communications (mMTC) is a key service category in ...

Please sign up or login with your details

Forgot password? Click here to reset